By way of example, an M2M application installed on a piece of M2M equipment uses a mobile operator network to allow a central server to interchange information remotely with this piece of equipment, in order to collect information stored on this equipment or to modify the state thereof without human intervention and especially without continuous human surveillance of the M2M equipment. To implement these interchanges of information for the mobile network, the equipment is provided with a card of USIM card type. M2M equipment, in the same way as a mobile subscriber terminal, is subjected to authentication from the network. More precisely, the USIM card is authenticated by the network on the basis of known authentication algorithms. However, in current network authentication procedures, the mobile equipment associated with the USIM card is not authenticated, either by the network or by the USIM card. It thus cannot be considered to be a piece of trustworthy equipment by the mobile network infrastructure.
Proposals have been made to overcome this problem. By way of example, the 3GPP document http://www.3gpp.org/ftp/tsg_sa/WG3_Security/TSGS3—61_Sorrento/DOcs/S3-101404.zip proposes a scheme for authenticating a USIM card in association with a mobile terminal into which the USIM card has been inserted. On the basis of this scheme, the network and the USIM card share an authentication key K in conventional fashion and the network and the terminal share a symmetrical key Kterminal. The authentication is thus performed according to the following steps:                the network sends a RAND challenge to the USIM card in conventional fashion,        the USIM card calculates a response by applying a known authentication algorithm F2 to the RAND challenge parameterized by the key K; it transmits the response to the terminal,        the terminal calculates a signature for this response using the symmetrical key belonging to the terminal Kterminal in order to produce a new response to the RAND challenge,        the new response is sent to the network,        the network can thus authenticate the terminal and the USIM card by verifying the signature of the received response, and the response as such.        
However, in the event of failure of the authentication by the network, this solution does not allow identification of whether the authentication error stems from the USIM card, from the terminal or from the two.